Technical Field
The present methods and systems relate to communications for a module, and more particularly, to methods and systems for supporting an embedded universal integrated circuit card (eUICC) in a module, where the module can securely and efficiently derive keys for communicating with a server and a wireless network, including shared secret keys and key pairs for use with public key infrastructure (PKI).
Description of Related Art
The combination of “machine-to-machine” (M2M) communications and using low-cost sensors, Internet connections, and processors is a promising and growing field. Among many potential benefits, M2M technologies allow the remote monitoring and/or control of people, assets, or a location where manual monitoring is not economic, or costs can be significantly reduced by using automated monitoring as opposed to manual techniques. Prominent examples today include vending machines, automobiles, alarm systems, and remote sensors. Fast growing markets for M2M applications today include tracking devices for shipping containers or pallets, health applications such as, but not limited to, the remote monitoring of a person's glucose levels or heartbeat, monitoring of industrial equipment deployed in the field, and security systems. Many M2M applications leverage either wired Internet connections or wireless connections, and both types of connections continue to grow rapidly. M2M applications may also be referred to as “the Internet of things”.
M2M communications can provide remote control over actuators that may be connected to a M2M device, such as, but not limited to, turning on or off a power switch, locking or unlocking a door, adjusting a speed of a motor, or similar remote control. A decision to change or adjust an actuator associated with an M2M device can utilize one or a series of sensor measurements. An M2M device may also be referred to as a “wireless module” or also simply a module. As one example, if a building or room is too cold, then temperature can be reported to a central server by an M2M device and the server can instruct the M2M device to turn on a switch that activates heat or adjusts a thermostat. As the costs for computer and networking hardware continue to decline, together with the growing ease of obtaining either wired or wireless Internet access for small form-factor devices, the number of economically favorable applications for M2M communications grows.
Many M2M applications can leverage wireless networking technologies. Wireless technologies such as, but not limited to, wireless local area networks and wireless wide area networks have proliferated around the world over the past 15 years, and usage of these wireless networks is also expected to continue to grow. Wireless local area network (LAN) technologies include WiFi and wireless wide area network (WAN) technologies include 3rd Generation Partnership Project's (3GPP) 3rd Generation (3G) Universal Mobile Telecommunications System (UMTS) and 4th Generation (4G) Long-term Evolution (LTE), LTE Advanced, and the Institute of Electrical and Electronics Engineers' (IEEE) 802.16 standard, also known as WiMax. The use of wireless technologies with “machine-to-machine” communications creates new opportunities for the deployment of M2M modules in locations less suitable for fixed-wire Internet access, but also creates a significant new class of problems that need to be solved.
One class of problems for using M2M modules with traditional wireless networks results from basic design considerations for the wireless networks, where many wireless wide-area networking standards were designed and optimized for mobile phones, including smart phones. A core element of traditional wireless WAN technologies such as 3GPP and ETSI standards over the past 20 years has included the use of a subscriber identity module (SIM) card within 2G networks and a related universal integrated circuit card (UICC) for 3G and 4G networks, including LTE networks. ETSI standards for a physical UICC as of 2013 include ETSI TR 102 216. Traditionally, these cards have been supplied by a mobile network operator (MNO) and contain a pre-shared secret key K in addition to a set of parameters for a mobile phone or user equipment to connect with the wireless network operated by the MNO. The parameters could include (i) an identity such as an IMSI, (ii) a set of frequencies for a mobile phone to scan in order to locate a beacon signal from the MNO, (iii) a preferred access list of other MNOs in order to support roaming in locations where the MNI associated with the IMSI is not available, and (iv) many other related parameters as well. The physical media and cards in the form of a UICC can be appropriate or suitable for a mobile phone or mobile handset, where an end user can readily replace or “swap out” the physical card as the mobile phone changes geographical locations or due to other preferences for the subscriber or end-user. Distributors of either mobile handsets or mobile phone service can physically insert or change an appropriate UICC for the mobile phones as well.
However, the rapid growth for “machine-to-machine” applications has created significant challenges to the traditional model of utilizing physical media such as a UICC in order to provide data and parameters for a module's connectivity to a MNO. Exemplary reasons for potential difficulties with physical media such as a UICC in M2M applications include (i) the modules may be installed in remote locations that are difficult or expensive to reach after installation, such as, but not limited to, tracking devices on shipping containers that can move globally, (ii) a manufacturer or service provider may prefer for the module to be hermetically sealed for business or technical reasons, including the physical UICC may not be easily tampered with, and (iii) a module (such as a tracking device on a 40 foot shipping container) may move between several different countries, and the lowest costs for Internet or data connectivity through the wireless WAN may be through utilizing different UICC cards from different operators, but the cost of swapping the UICC card could be prohibitive.
Other needs for changing a preferred network or network credentials without physically changing a UICC exist as well. These needs have been one motivation for the industry, including ETSI and 3GPP standards bodies, to consider an embedded UICC, also known as an “eUICC”. With an eUICC, the operation of an UICC can be essentially “virtualized”, such that the data and algorithms within a UICC can be processed in software and distributed through electronic media (such as, but not limited to, a file transfer or file download). Exemplary benefits and technical considerations for using an eUICC in M2M applications as of November 2013 is outlined in ETSI TS 103 383 v12.1, entitled “Smart Cards; Embedded UICC; Requirements Specification,” which is herein incorporated by reference in its entirety. Note that this published standard from September 2013, and the standard is primarily in the requirements definition phase, and many of the technical specifications for implementation and operation of an eUICC will be defined in the future.
Although the use of an embedded eUICC can solve many of the issues for distributing and managing physical media such as a UICC, many additional challenges remain. Many open and remaining challenges for a eUICC pertain to securely and electronically transferring a new set of MNO network access credentials (such as an IMSI and network key K) to a module in a secure and efficient manner. A need exists in the art for a module to securely obtain network access credentials. Another need exists in the art for the obtained credentials in a eUICC to be fully compatible with the significant installed and legacy base of networks that use a pre-shared secret key K, where the key K serves as the foundation for authentication and ciphering of data for a mobile phone or user equipment, including modules using conventional technology. A successful solution to these needs for M2M applications in the form of an eUICC can also provide a working solution of the needs for regular mobile phones as well, such that a consumer mobile phone could implement and utilize an eUICC in order to eliminate the costs and complexity of dealing with a physical UICC.
A need exists in the art for module and a mobile network operator to securely share a pre-shared secret key K without depending on physical distribution of the key K or electronic distribution of the key K through 3rd parties, even in an encrypted form. As currently contemplated in November of 2013 by eUICC standards discussed above, a pre-shared secret key K and related network access credentials are transmitted to a module in an encrypted form, including multiple potential layers of encryption and authentication. The pre-shared secret key K is also known as key K in 4G LTE and related networks and key Ki in 3G networks. The resulting security for the electronically transferred, pre-shared secret key K is no stronger than (i) the encryption on the channel used to transfer key K, and (ii) the security and chain of control for keys used to encrypt the communications channel transferring key K to a module or a mobile phone. The MNO using an electronically transferred key K for network access credentials is dependent on the communications channel for transferring key K, even though that communications channel may be outside the control of the MNO (such as at a time when key K is transferred using another MNO or a different network).
In addition, over an extended period of time such as several years, a mobile network operator could prefer for the key K to periodically rotate or change for an individual module or mobile phone in order to increase security. The continued and extended use of a single key K for all communications with a module or mobile phone can be a security risk, especially with a large volume of data transferred that could be subject to analysis for cryptographic weaknesses by potential attackers. Additionally, in the future a standard key length for key K may increase from today's current 128 bits to a longer key length such as an exemplary 256 bits. With conventional technology where key K is recorded in physical media such as a UICC, the only feasible way to change key K for a module or mobile phone is to physically distribute a new UICC card, with resulting costs and business complexities. A need exists in the art for a module, including a mobile phone, and a MNO to securely and efficiently support a change in network access credentials, including a key K for the module connecting to the MNO, without requiring a physical replacement of a UICC or equivalent physical media recording a key K.
And other needs exist in the art as well, as the list recited above is not meant to be exhaustive but rather illustrative.